In Math.SE I can visit the 'Edit profile and settings' page and edit my display name, location, etc. But when I tried to upload a new profile image from my computer, it always fail.
Also, I can only view users' default profile images. I suppose that other users' images, which is blank from my point of view, should be images they uploaded themselves that my browser failed to load.
Is that only users with enough reputation can change their profile images, or there's some problem with the system? Thank you for helping me.